Muerte neuronal en la neocorteza de pacientes con epilepsia del lóbulo temporal resistente a fármacos / Neuronal death in the neocortex of drug resistant temporal lobe epilepsy patients

Introducción. La participación de mecanismos de muerteapoptótica en la epilepsia del lóbulo temporal resistente afármacos (ELTRF) es un aspecto muy discutido en la actualidad.Investigamos si existe pérdida neuronal y la inmunodeteccióna diferentes marcadores de muerte en tejido neocorticalen ocho pacientes con ELTRF y como tejido controlse evaluaron cinco neocortezas de sujetos fallecidos porcausas no neurológicas, pareados en edad y sexo.Métodos. La evaluación de la pérdida neuronal se realizópor medio de un estudio estereológico y por técnica inmunohistoquímicacon el marcador sinaptofisina. Se evaluóla inmunopositividad a diferentes marcadores apoptóticos(anexina V, caspasa 3 y 8, bcl-2 y p53), así como la detecciónde fragmentación del ácido desoxirribonucleico (ADN) (TUNEL),y se realizó en todos los casos un doble marcaje con sinaptofisina.Los resultados fueron evaluados por microscopiaconfocal y analizados por el programa Zeiss LSM 5 ImageBrowser, 2.80.1113 (Alemania).Resultados. Se observó una disminución estadísticamentesignificativa del número total de células (p<0,05), asícomo de las células sinaptofisina+ (p<0,01) en la neocorteza(capa IV) de los pacientes con ELTRF al ser comparadoscon el tejido control. No mostraron diferencias significativaslos marcadores apoptóticos bcl-2, p53, caspasa 3 y 8 paraninguna de las capas de neocorteza, mientras que sí resultóestadísticamente aumentado el número de células TUNEL+(p<0,05) y anexina V+ (p<0,05) en la capa IV neocortical delos pacientes.Conclusiones. Este grupo de evidencias hablan a favorde la existencia en la capa IV de neocorteza de una afectaciónen el número neuronal que se puede asociar a un procesode muerte apoptótica por una vía no dependiente de caspasas,sin que pueda ser descartada la muerte por necrosis (AU)

Introduction. Participation of apoptotic death mechanisms in drug resistant temporal lobe epilepsy (DRTLE) is currently under great debate. We have investigated if there is neuronal loss and the immunodetection to differentmarkers in neocortical tissue death in eigth patients with DRTLE. The neocortexes of five patients deceased due to non-neurological causes, paired in age and gender were evaluated as control tissue. Methods. The evaluation of neuronal loss was made by means of a stereological study and with immunohisto chemical techniques with the synaptophysin marker. Immunopositivity to different apoptotic markers (annexin V, caspase 3 and 8, bcl-2 and p53) and detection of deoxyribonucleic acid (DNA) fragmentation (TUNEL) wereanalyzed and double labeling with synaptophysin was performed in every case. The results were evaluated with confocal microscope and analyzed with the Zeiss LSM 5 Image Browser Program, 2.80.1113 (Germany). Results. A statistically significant decrease in the total number of cells (p < 0.05) and the synaptophysin cells+ (p<0.01) in the neocortex (layer IV) of the patients with DRTLE when compared with the control tissue was found. No significant differences were found in the apoptotic markers bcl-2, p53, caspase 3 and 8 for any of the neocortex layers while there was a statistically significantincrease in the number of TUNEL cells+ (p<0.05) and annexin V+ (p<0.05) in the neocortical layer IV of the patients. Conclusions. This group of evidence speaks in favor of the existence of an effect on the neuronal number in the neocortex layer IV that may be associated with non caspase dependent apoptotic death process, without beingable to rule out death by necrosis

[Neuronal death in the neocortex of drug resistant temporal lobe epilepsy patients]. / Muerte neuronal en la neocorteza de pacientes con epilepsia del lóbulo temporal resistente a fármacos.

Introduction. Participation of apoptotic death mechanisms in drug resistant temporal lobe epilepsy (DRTLE) is currently under great debate. We have investigated if there is neuronal loss and the immunodetection to different markers in neocortical tissue death in eigth patients with DRTLE. The neocortexes of five patients deceased due to non-neurological causes, paired in age and gender were evaluated as control tissue. Methods. The evaluation of neuronal loss was made by means of a stereological study and with immunohistochemical techniques with the synaptophysin marker. Immunopositivity to different apoptotic markers (annexin V, caspase 3 and 8, bcl-2 and p53) and detection of deoxyribonucleic acid (DNA) fragmentation (TUNEL) were analyzed and double labeling with synaptophysin was performed in every case. The results were evaluated with confocal microscope and analyzed with the Zeiss LSM 5 Image Browser Program, 2.80.1113 (Germany). Results. A statistically significant decrease in the total number of cells (p < 0.05) and the synaptophysin cells+ (p<0.01) in the neocortex (layer IV) of the patients with DRTLE when compared with the control tissue was found. No significant differences were found in the apoptotic markers bcl-2, p53, caspase 3 and 8 for any of the neocortex layers while there was a statistically significant increase in the number of TUNEL cells+ (p<0.05) and annexin V+ (p<0.05) in the neocortical layer IV of the patients. Conclusions. This group of evidence speaks in favor of the existence of an effect on the neuronal number in the neocortex layer IV that may be associated with noncaspase dependent apoptotic death process, without being able to rule out death by necrosis. Key words: Drug resistant temporal lobe epilepsy. Apoptosis. Necrosis. Neuronal loss. Neurología 2008;23(9):555-565.